What is the longest word in English?

Longest words in English?

The Oxford University Press English Dictionary disqualifies the word nominated by The Readers Digest with this withering put down: 

“a factitious word alleged to mean 'a lung disease caused by inhalation of very fine silica dust usually found in volcanos' but occurring chiefly as an instance of a very long word”.

In its place, OUP nominates loccinaucinihilipilification (29 letters) as the longest genuine word, followed by antidisestablishmentarianism (28 letters). 

Another rival for the 'longest word you ever heard' has 34 letters and features in a certain film. 

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